Packageable shelter with radio frequency shielding



March 1969 w. c. DUVALL ET AL 3,432,609 PACKAGEABLE SHELTER WITH RADIO FREQUENCY SHIELD-INC:

Filed Nov. 25, 1966 Sheet 01 2 INVENTORS WILLIAM c. DUVALL wILLIAM R. LUDWICK ALBERT E. BRION, JR.

ATTOBNEY March 11, 1969 w. c. DUVALL ET Al, 3,432,609

PACKAGEABLE SHELTER WITH RADIO FREQUENCY SHIELDING Sheet Filed Nov. 25, 1966 INVENTORS WILLIAM C. DUVALL WILLIAM R. LUDWICK ALBERT E. BRION,JR.

ATORNE United States Patent O 8 Claims ABSTRACT OF THE DISCLOSURE The technical disclosure, shown in this application, is a packageable shelter made from an assembly of dual wall inflatable fabric panels connected to-geher by strap type fasteners. All these panels have a coating of radio reflective material such as silver-coated nylon cloth. All the joints of this shelter, where to adjacent panels are connected together either to form the walls, the roof, or the floor of the shelter, are provided with strips of radio reflective wire screen, such as Monel wire, to provide radio reflective continuity at all the joints and throughout the entire structure. Each panel edge has a connection strip of such wire screen which is clamped in metal-tometal contact with a similar connection strip on the adjacent panel. A similar type joint is used to connect the door frame to the Wall panels and the wall panels to the floor to provide radio reflective continuity at these joints.

This invention relates to a packageable shelter for shielding personnel and equipment from radio frequency radiation, such as radar waves and the like, and, in particular, to a shelter made of a plurality of individual panels assembled together with a joint structure which provides continuity of radio frequency shielding throughout the entire shelter.

In the past, numerous types of prefabricated packageable shelters have been made in the form of a balloonlike structure which is supported by air pressure throughout the entire interior of the shelter. Other inflatable shelters maintain their contour by inflation of tubular supporting members in the walls. Still other structures are formed of a plurality of double-walled inflatable panels which maintain their rigidity by internal pressure within each double-walled panel, thus eliminating the need of maintaining internal pressure within the interior of the structure per se. Structures using such double walled panels are well known in the prior art. One typical example of such a structure is shown in Patent No. 2,908,- 919 issued to R. Bicknell et al.

A more detailed description of such double-walled panels may be found in Patent No. 2,743,5 issued to P. Mauney et al., which shows the manner in which a plurality of tie threads are interwoven with each of the two sheets of fabric forming the walls of the panel. Panels of this type are manufactured by The Goodyear Tire & Rubber Company under the trademark Airmat. In the interest of brevity, such panels will hereafter be referred bled and disassembled by personnel having a minimum of instruction or experience in handling this type of structure.

These and other objects of the invention will become apparent from the following specification and the attached drawings in which:

FIG. 1 is a perspective view of a shelter of the type contemplated by this invention with portions broken away to more readily reveal the structure;

FIG. 2 is a fragmentary perspective view showing the manner of joining together a Wall panel and a roof panel;

FIG. 3 is a fragmentary perspective view showing the manner of joining together two wallpanels to form an outside wall corner;

FIG. 4 is a fragmentary cross-sectional view showing the manner of attaching a radio frequenc shielding connection strip to one of the panels; and

FIG. 5 is a fragmentary cross-sectional view showing a typical shielded joint between the floor and walls.

Referring now to the drawings and, in particular, to FIG. 1 a typical packageable inflatable shelter is indicated generally by the numeral 1. The shelter is made up of a plurality of wall panels 2, a roof panel 3, a pair of roof trusses 4, and a floor 5. The panels are made of inflatable dual wall fabric and produced by The Goodyear Tire & Rubber Company under the trademark Airmat. One or more of the wall panels 2 may be provided with a door 6.

for access to and from the interior of the shelter. All the adjoining edges of the wall panels 2, the roof panel 3, and the roof trusses 4 are provided with a suificient number of strap connectors 7, which will be described later in more detail, for fastening together the panels. All the panels are provided with a weather strip 8 which covers all the panel joints on the exterior of the shelter to prevent Wind and rain from passing through the joints between the panels. The weather strip 8 has one edge permanently secured to one of the panels and the other edge is provided with suitable snaps 9 for securing the free edge to the adjoining panel. For the sake of clarity, the details of the joint structure which provides radio frequency shielding has not been shown in FIG. 1. Thepurpose of FIG. 1 is merely to show the overall arrangement of the panels and the manner in which they are assembled together to form this particular shelter configuration.

Referring now to FIG. 2 of the drawings, a wall panel 2 and a roof panel 3 are shown in a typical position for assembling. A pair of strap connectors 7 are shown attached to the panels with part of each connector located on the wall panels 2 and a mating part located on the panel 3. The portion of connectors 7 located on the wall panel 2 consists of a generally triangular shaped patch 10 secured to the panel by sewing or by any suitable adhesive. A strap 11 extends from the patch 10 and supports thereon a buckle 12. One of the patches 10 with the strap 11 and buckle 12 is secured to the outside wall 13 of the panel 2, and the other patch 10 is secured to the inside wall 14 of the panel 2. Attached to the edge of the panel 3 is a patch 15 which supports a pair of straps 16, each of which carries a loop 17 on the end thereof to which the buckle 12 is fastened. As may be seen from FIG. 2, the strap 16, which is attached to the part of patch 15 on the inside wall 18 of the panel 3, connects to the buckle 12 located on the outside of the panel 2. The other strap 16, which is attached to the part of the patch 15 on the outside wall 19 of the panel 3, connects to the buckle 12 located on the inside wall of the panel 2. A typical weather strip 8 is shown in FIG. 2 with one edge attached to the panel 3 and the other edge having a plurality of snaps 9 which engage a male snap portion 20 located in the required position along the outside wall 13 of the panel 2. Each of the panels 2 and 3 has a radio frequency radiation shielding layer 21 secured to the inside wall of each panel. The layer 21 consists of a silver-coated nylon cloth which covers the interior wall of each panel and is preferably secured thereto by any suitable adhesive.

Attached to the edge of the shielding layer 21 is one edge of a flexible metallic radio frequency reflective connection strip 22 which forms a reflectively continuous extension of the shielding layer 21. The connection strips 22, however, are attached to the panels 2 and 3 only where their edges join with the edge of the shielding layer 21. The other edge of each strip 22 is a free edge which has a thickened reinforcing rib 23 for attachment to a similar rib 23 on the connection strip 22 of the adjacent panel. A plurality of resilient C-shaped clips 24 are clamped over the two adjacent ribs 23 at a suflicient number of locations along their length to hold them in intimate contact with each other throughout their length.

The specific structural details of the connection strips 22 and the manner in which they attach to the shielding layers 21 will be described hereafter in greater detail and is illustrated in FIG. 4.

An outside corner wall is shown in FIG. 3, which shows a pair of wall panels 2 fastened together by a typical strap connector 7. The arrangement of the strap connector 7 in this particular joint differs from that shown in FIG. 2 where two strap connectors 7 are used with each connector crossing over from the inside wall of one panel to the outside wall of the panel to which it is being connected. In FIG. 3 the strap connector simply passes from the outside wall of one panel around the corner to the outside wall of the adjacent panel. A typical weather strip 8 is shown covering the joint between the panels 2. Each of the panels 2 has a shielding layer 21 and a connection strip 22 extending from the edge thereof in the same manner as shown in FIG. 2. The free edges of the connection strips 22 are likewise held together by a plurality of clips 24. The manner of joining the connection strips 22 to the shielding layer 21 and to each of the panels 2, 3, or 4 is similar regardless of which panels are being joined and of whether it is a joint between two wall panels or between a wall panel and a roof panel or roof truss.

A typical construction of such connection strip is shown in FIG. 4, in which the connection strip 22 is formed by folding a layer of metallic wire screen 25 around the edge of the shielding layer 21 so that the screen 25 covers a predetermined width of material on each side of the shielding layer 21 along the edge thereof.

The reinforcing rib 23, described previously and shown in FIGS. 2 and 3, is formed by wrapping a strip 26 of silver-coated nylon cloth around a nylon rope 27 in such manner that the two edges of the strip 26 are adjacent to each other and form a tab 28 running the length of the rope. The tab 28 is then adhered to the outer edge of the shielding layer 21. The wire screen 25 is then placed against one side of the shielding layer 21 and then folded around the cloth-encased rope 27 to extend along the opposite side of the shielding layer 21. The wire screen 25 is then sewed to the shielding layer 21 along the outer edge of the connection strip 22 just inwardly of the rib 23 and along the inner edge of the screen 25. A strip of tape 29 has one portion secured to the outside face of the connection strip 22 near the inside edge thereof, and the other portion secured to the panel 2. This tape 29 prevents the shielding layer 21 from being pulled away from the panel 2 due to stresses upon the connection strip 22 during handling or erection of the panels.

The entire portion of the shielding layer 21, which is adhered to the panel 2, may be covered with a protective coating such as urethane, or the like, to prevent corrosion of the silver coating on the nylon cloth. The wire screen 25 used in the connection strip 22 must not be coated, however, with such a protective coating since it is necessary to have continuous metal-to-metal contact between each adjacent connection strip 22 which is joined together. Such metal-to-metal contact is necessary to provide reflective continuity at all such joints. Since a protective coating may not be used on the screen 25, the screen should be made from a corrosion-resistant metal such as Monel wire.

It will, of course, be understood that the floor 5 and the door 6 must also be provided with continuous metalto-metal contact with the shielding layers 21 of all the adjacent panels. The door 6 is preferably made of metal or at least contains a sufficient metallic coating to provide the necessary radio reflectivity that is present in the rest of the shelter.

The door 6 may be mounted in a metallic door frame 30 which is attached to the wall panel 2 in metal-to-rnetal contact in a manner similar to that described for joining together the adjacent panels.

The floor 5 must also be made of metal or at least contain some type of metal coating over its entire surface. In joining the floor 5 to the wall panels 2 (FIG. 5), a connection strip 22, similar to that shown in FIG. 4, may be attached to the shielding layer 21 at the bottom edges thereof and overlap a metallic shielding layer 31 on the floor 5.

It will be understood that the specific manner of constructing the connection strip 22, which is shown in FIG. 4, is only one of several ways that this strip may be made. For example, the portion of the shielding layer 21 which is surrounded on both sides by the wire screen 25 need not be an integral part of the layer 21 but may be attached as a separate strip so long as the proper metal-to-metal contact of the silver coating is maintained to thereby provide the required reflective continuity. The wire screen 25 need not cover both sides of the connection strip 22. The connection strip 22 may be merely a strip of metallic screen attached in metal-to-metal contact with the edge of the silver-coated nylon cloth of the shielding layer 21. The primary reason for extending the nylon cloth shielding layer coextensively with the screen 25 is that it serves as a stiffener or support for the screen. All that is necessary for continuity of shielding, however, is that there be metal-to-metal contact between the shielding layer 21 and the wire screen 25 and that when two adjacent connection strips 22 are fastened together there is bare metal exposed by the wire screen 25 all along the edges thereof to provide the proper reflective continuity.

This shielded joint may also be used with other types of radio reflective panels and is not restricted merely to use with the Airmat panels described herein.

Various changes can be made in the illustrative embodiments shown herein without departing from the scope of the invention.

We claim:

1. A packa geable shelter for shielding personnel and equipment from radio frequency radiation comprising:

(A) a plurality of individual inflatable panels each panel having;

( 1) a radio frequency reflective layer covering at least one side of the panel,

(2) a flexible, metallic radio frequency reflective connection strip extending around the entire edge of each panel,

(a) having one edge attached to said reflective layer around the edge thereof and forming a reflectively continuous extension therefrom, and

(b) said connection strip having a free edge attached to a similar strip on an adjoining panel,

(B) means mechanically fastening together all the panels of the shelter in a predetermined edge-to-edge relationship to form the required shelter configuration; and

(C) means removably joining together the adjacent free edges of the connection strips to provide radio reflective continuity at each joint.

2. A shelter as claimed in claim 1 wherein each panel has an inner surface covered by the radio frequency reflective layer and wherein each connection strip has at least one layer of corrosion-resistant metallic screen attached in metal-to-metal contact with the edge of the radio frequency reflective layer.

3. A shelter as claimed in claim 2 wherein the reflective layer is silver-coated nylon cloth.

4. A shelter as claimed in claim 2 including at least one metallic floor panel the edges of which lie on top of a connection strip on each adjoining Wall panel to provide reflective continuity at the wall and floor joints.

5. A joint structure for fastening together adjacent edges of radio frequency reflective panels to form an assembly having continuity of shielding throughout comprising:

(A) a pair of radio reflective inflatable panels to be joined;

(B) a connection strip of flexible metallic radio frequency' reflective material attached to each panel 6. A joint structure as claimed in claim 5 wherein each connection strip has at least one layer of corrosion resistant metallic screen attached in metal-to-metal contact with the edge of a radio frequency reflective layer covering each panel.

7. A joint structure as claimed in claim 6 wherein the reflective layer covering each panel is silver-coated nylon cloth.

8. A joint structure as claimed in claim 7 wherein the reflective layer is covered with a protective coating to prevent corrosion of the silver, but the metallic screen of each connection strip is used without a protective coating to provide metal-to-metal contact with the connection strip to which it is joined.

References Cited UNITED STATES PATENTS 3,390,491 7/ 1968 Hayden et al. 522 2,876,275 3/ 1959 Schulz 174-35 3,030,435 4/1962 Andrews 17435 FOREIGN PATENTS 810,814 3/1959 Great Britain.

DARRELL LQCLAY, Primary Examiner.

US. Cl. X.R. 

